The way I see it, S is an insecure control freak and is making a mountain out of a molehill. Are you seriously going to put her in charge of your life, who you are "allowed" to date (ridiculous!), and even whom you may speak to? I personally would not tolerate that bullshit from anyone. Wow.

Your responsibility is to manage your relationships and hers is to manage her relationships. But she doesn't have a right to manage your other relationships (by that I mean, those she is not a part of!). Doing that is just a dictatorship. She should just worry about her relationship with you and not what kinds of conversations you are having with anyone else. Sheesh. Sounds like junior high.